# US 10,872,550 B2 · Display driver and displaying method for cascade application > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,872,550 B2 - Document ID: US10872550B2 - Status: Granted - Kind: B2 - Application number: 16/365,711 - Filed: 2019-03-27 - Published: 2020-10-01 - Granted: 2020-12-22 - Earliest claimed: 2019-03-27 - Assignees: Novatek Microelectronics Corp. - Applicants: Novatek Microelectronics Corp. - Inventors: Jen-Wei Li; Jen-Hao Liao - Web page: https://patentgrep.com/patent/US10872550B2 ## CPC - G09G 3/20: for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix {no fixed position being assigned to or needed to be assigned to the individual characters or partial characters} - G09G 3/3685: {Details of drivers for data electrodes} - G09G 2310/0243: Details of the generation of driving signals - G09G 2310/027: Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters - G09G 2310/0291: Details of output amplifiers or buffers arranged for use in a driving circuit - G09G 2310/0297: Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns - G09G 2320/0276: for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction - G09G 2320/0673: for control of gamma adjustment, e.g. selecting another gamma curve - G09G 2330/028: Generation of voltages supplied to electrode drivers in a matrix display other than LCD - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A display driver that includes a first driver integrated circuit being cascaded to a second driver integrated circuit is introduced. The first driver integrated circuit includes a first gamma voltage generator that is configured to output a plurality of first gamma voltages to output terminals of the first gamma voltage generator. The second driver integrated circuit includes a second gamma voltage generator that is configured to output a plurality of second gamma voltages to output terminals of the second gamma voltage generator. Each of the output terminals of the first gamma voltage generator is corresponded to one of the output terminals of the second gamma voltage generator. At least one of the output terminals of the first gamma voltage generator is electrically coupled to the corresponding one of the output terminals of the second gamma voltage generator to output at least one common gamma voltage of the first gamma voltages and the second gamma voltages. A method adapted to the display driver is also introduced. ## Claims ### Claim 1 A display driver, comprising: a first driver integrated circuit, comprising a first gamma voltage generator configured to output a plurality of first gamma voltages to output terminals of the first gamma voltage generator, a second driver integrated circuit, comprising a second gamma voltage generator configured to output a plurality of second gamma voltages to output terminals of the second gamma voltage generator, wherein each of the output terminals of the first gamma voltage generator is corresponded to one of the output terminals of the second gamma voltage generator, wherein the first driver integrated circuit cascaded to the second driver integrated circuit, at least one of the output terminals of the first gamma voltage generator is electrically coupled to the corresponding one of the output terminals of the second gamma voltage generator to form a common output terminal, and at least one common gamma voltage of the first gamma voltages and the second gamma voltages is outputted to the common output terminal. ### Claim 2 (depends on 1) The display driver of claim 1, wherein the first driver integrated circuit further comprises a first source driver circuit being coupled to the first gamma voltage generator, the first source driver circuit is configured to drive a display panel according to the at least one common gamma voltage, the second driver integrated circuit further comprises a second source driver circuit being coupled to the second gamma voltage generator, the second source driver circuit is configured to drive the display panel according the at least one common gamma voltage. ### Claim 3 (depends on 2) The display driver of claim 2, wherein the at least one common gamma voltage comprises a first common gamma voltage, the first common gamma voltage is generated by either the first gamma voltage generator or the second gamma voltage generator, and the first common gamma voltage is outputted to both of the first source drive circuit and the second source drive circuit. ### Claim 4 (depends on 3) The display driver of claim 3, wherein the first gamma voltage generator comprises: a plurality of first buffers, each of the first buffers is configured to generate one of the first gamma voltages, and a first resistor string, configured to generate at least one of the first gamma voltages, and the second gamma voltage generator comprises: a plurality of second buffers, each of the second buffers is configured to generate one of the second gamma voltages; and a second resistor string, configured to generate at least one of the second gamma voltages. ### Claim 5 (depends on 4) The display driver of claim 4, wherein each of the first buffers is corresponded to one of the second buffers, the first common gamma voltage is generated by either one of the first buffers or the corresponding one of the second buffers, wherein the one of the first buffers is electrically connected to the corresponding one of the second buffers. ### Claim 6 (depends on 5) The display driver of claim 5, wherein only one of the one of the first buffers and the corresponding one of the second buffers is turned on at a time. ### Claim 7 (depends on 5) The display driver of claim 5, wherein the first gamma generator further comprises a first switch coupled between an output terminal of the one of the first buffers and the output terminal of the first gamma generator, the second gamma generator further comprises a second switch coupled between an output terminal of the corresponding one of the second buffers and the output terminal of the second gamma generator, and only one of the first switch and the second switch is turned on at a time. ### Claim 8 (depends on 4) The display driver of claim 4, wherein each node in the first resistor string is corresponded to a node in the second resistor string, the first common gamma voltage is generated by either one node of the first resistor string or the corresponding node of the second resistor string, wherein the one node of the first resistor string is electrically connected to the corresponding node of the second resistor string. ### Claim 9 (depends on 4) The display driver of claim 4, wherein each of the first gamma voltage generator and the second gamma voltage generator comprise a multiplexer configured to select m common gamma voltages among n gamma voltages, wherein n and in are natural numbers, and n is greater than m, and each of the m common gamma voltages is generated by either the first gamma voltage generator or the second gamma voltage generator. ### Claim 10 (depends on 9) The display driver of claim 9, wherein m output terminals of the first gamma voltage generator are selected to be coupled to m corresponding output terminals of the second gamma voltage generator through m connection lines, and the first buffers that are related to the m connection lines and the second buffers that are related to the m connection lines are controlled such that the common gamma voltage in each of the in connection lines is generated by either an output terminal of first gamma voltage generator or a corresponding output terminal of the second gamma voltage generator. ### Claim 11 (depends on 10) The display driver of claim 10, wherein them connection lines include a connection line that connects one of the first buffers to a corresponding one of the second buffers, and either one of the first buffers or the corresponding one of the second buffers are turned on at a time to output a common gamma voltage in the connection line. ### Claim 12 (depends on 10) The display driver of claim 10, wherein the m connection lines include a connection line that connects a node of the first resistor string to a corresponding node of the second resistor string, and the first buffers that are related to the node of the first resistor string and the corresponding second buffers that are related to the corresponding one of the second resistor string are controlled such that one of the first buffers that are related to the node of the first resistor string or a corresponding one of the second buffers that are related to the corresponding node of the second resistor string is turned on at a time. ### Claim 13 A method adapted to a display driver having a first driver integrated circuit being cascaded to a second driver integrated circuit, the first driver integrated circuit comprising a first gamma voltage generator and the second driver integrated circuit comprising a second gamma voltage generator, the method comprising: selecting m output terminals among n output terminals of the first gamma voltage generator to be electrically coupled to m corresponding output terminals among n output terminals of the second gamma voltage generator to form m common output terminals; generating m common gamma voltages and outputting the m common gamma voltages to the m common output terminals, wherein each of the m common gamma voltages is generated by either the first gamma voltage generator or the second gamma voltage generator; providing the m common gamma voltages to the first driver integrated circuit and the second driver integrated circuit. ### Claim 14 (depends on 13) The method of claim 13, wherein the first driver integrated circuit further comprises a first source drive circuit being coupled to the first gamma voltage generator, the second driver integrated circuit further comprises a second source drive circuit being coupled to the second gamma voltage generator, and the m common gamma voltages are provided to both of the first source drive circuit and the second source drive circuit.